Rotational Atherectomy Device With Fluid Inflatable Support Elements And Distal Protection Capability

ABSTRACT

A rotational atherectomy device for abrading a stenotic lesion from a vessel of a patient comprises a flexible drive shaft ( 1 ) which extends towards a distal end of the device, a distal fluid inflatable support element ( 3, 3 ″) located at a distal end of the drive shaft and an abrasive element ( 5 ) mounted to the drive shaft proximal to and spaced away from the distal fluid inflatable support element. Both the abrasive element and the distal fluid inflatable support element are rotatable together with the drive shaft and the drive shaft comprises a torque transmitting coil ( 2 ) which defines a long lumen of the drive shaft. The distal fluid inflatable support element is formed from a fluid impermeable membrane ( 9, 9 ″) that crosses a longitudinal axis (x-x) common to the torque transmitting coil and the lumen of the drive shaft at the distal end of the device, thereby preventing pressurized fluid flowing along the lumen of the drive shaft from entering the vessel in the direction of said longitudinal axis so that fluid has to pass through the fluid inflatable support element, inflating said support element and exiting from the device through an outflow opening ( 66 ) in the fluid inflatable support element in a direction different from the direction of the longitudinal axis of the coil and the lumen.

The present invention relates to a rotational atherectomy device forremoving or reducing stenotic lesions in blood vessels such as a humanartery by rotating an abrasive element within the vessel to partially orcompletely ablate the unwanted material.

Atherosclerosis, the clogging of arteries, is a leading cause ofcoronary heart disease. Blood flow through the peripheral arteries(e.g., carotid, femoral, renal etc.), is similarly affected by thedevelopment of atherosclerotic blockages. One conventional method ofremoving or reducing blockages in blood vessels is known as rotationalatherectomy. A long guidewire is advanced into the diseased blood vesseland across the stenotic lesion. A hollow drive shaft formed from atorque transmitting coiled wire(s) is advanced over the guidewire. Thedistal end of the drive shaft terminates in a burr provided with anabrasive surface formed from diamond grit or diamond particles. The burris positioned against the occlusion and the drive shaft rotated atextremely high speeds (e.g., 20,000-160,000 rpm).

As the burr rotates, the physician slowly advances it so that theabrasive surface of the burr scrapes against the occluding tissue anddisintegrates it, reducing the occlusion and improving the blood flowthrough the vessel. Such a method and a device for performing the methodare described in, for example, U.S. Pat. No. 4,990,134 to Auth. It isalso known from U.S. Pat. No. 6,132,444 to Shturman (the instantinventor) et al., to provide a drive shaft which is also formed from asingle layer of torque transmitting coiled wire or wires but differentto the device described in U.S. Pat. No. 4,990,134 to Auth, mentionedabove, by providing the drive shaft with an eccentric enlarged diametersection located proximally to and spaced away from the distal end of thedrive shaft. This drive shaft is formed from a single layer of torquetransmitting coiled wire(s). According to U.S. Pat. No. 6,132,444 toShturman, abrasive particles are located around a maximum diameter ofthe eccentric segment of the drive shaft thereby forming an eccentricabrasive element positioned proximally to and spaced away from thedistal end of the drive shaft.

A rotational atherectomy device with distal embolic protectioncapability is known from WO 2006/126076 to Shturman (the currentinventor). In one preferred embodiment of this known Shturmanapplication the distal end of the fluid impermeable drive shaft isadvanced across the stenotic lesion to be treated and flushing fluid ispumped through the drive shaft in an antegrade direction to enter thevessel through at least one luminal opening located distally to theabrasive element. As a result of a continued flow of flushing fluid intothe vessel in this way, a fluid pressure is generated in the vesseldistal to the abrasive element which is sufficient to generate aretrograde flow of at least a portion of the flushing fluid around theabrasive element and the fluid impermeable drive shaft. This retrogradeflowing flushing fluid entrains stenotic debris abraded by the rotatingabrasive element and flows into a lumen of stationary drive shaft sheaththereby preventing distal migration of debris along the treated vessel.In the most preferred embodiment, abraded debris are not only beingremoved from the treated vessel but from the patient altogether.

According to the preferred embodiments of WO 2006/126076, it is alsopossible to provide inflatable support elements located distal andproximal to the abrasive element. The inflatable support elements mayhave centres of mass which are offset from the longitudinal axis of thedrive shaft. Such support elements act as counterweights to theeccentric abrasive element, i.e. an abrasive element that has its centreof mass offset from the longitudinal axis of the drive shaft.Alternatively, the abrasive element and the support elements may havecentres of mass which lie along the longitudinal axis of the driveshaft.

The rotational atherectomy device with fluid inflatable support elementshas a smaller crossing profile than the rotational atherectomy devicewith solid support elements. The term ‘crossing profile’ refers to amaximum cross-sectional dimension of that portion of the device whichhas to be advanced across the stenotic lesion.

All embodiments of the device described in WO 2006/126076 have to beadvanced along the treated vessel and across the stenotic lesion overthe guidewire. The devices with fluid inflatable support elements knownfrom WO 2006/126076 allow to reduce the crossing profile of the driveshaft of the device but they still have to be advanced across thestenotic lesion over the guidewire. The outer diameter of the driveshaft of any rotational atherectomy device with distal protection whichis advanced over a guidewire may still be too large to cross very tightstenotic lesions. The present invention therefore seeks to provide arotational atherectomy device with distal protection capability whichdoes not require use of a guidewire for its advancement across thestenotic lesion to be treated. Such device may have a crossing diameterwhich is smaller than the crossing diameter of known rotationalatherectomy devices with distal protection capability. The presentinvention also seeks to provide a rotational atherectomy device withdistal protection capability that does not require occlusion of a distalend of the guideiwre lumen prior to initiating flow of pressurized fluidthrough the guidewire lumen.

According to the present invention, there is provided a rotationalatherectomy device for abrading a stenotic lesion from a vessel of apatient comprising a flexible drive shaft which extends towards a distalend of the device, a distal fluid inflatable support element located ata distal end of the drive shaft and an abrasive element mounted to thedrive shaft proximal to and spaced away from the distal fluid inflatablesupport element, both the abrasive element and the distal fluidinflatable support element being rotatable together with the driveshaft, the drive shaft comprising a torque transmitting coil whichdefines a long lumen of the drive shaft, the distal fluid inflatablesupport element being formed from a fluid impermeable membrane thatcrosses a longitudinal axis common to the torque transmitting coil andthe lumen of the drive shaft at the distal end of the device, therebypreventing pressurized fluid flowing along the lumen of the drive shaftfrom entering the vessel in the direction of said longitudinal axis sothat fluid has to pass through the fluid inflatable support element,inflating said support element and exiting from the device through anoutflow opening in the fluid inflatable support element in a directiondifferent from the direction of the longitudinal axis of the coil andthe lumen.

Preferably, this fluid impermeable membrane forms a wall of the distalfluid inflatable support element.

Preferably, the wall of the distal fluid inflatable support elementextends around the torque transmitting coil of the drive shaft.

The wall of the distal fluid inflatable support element is preferablybonded to a surface of the torque transmitting coil proximal to thedistal fluid inflatable support element.

In a preferred embodiment, the torque transmitting coil comprises atleast one space which separates individual windings of the coil, saidspace allowing fluid communication between the lumen of the drive shaftand the distal fluid inflatable support element.

A preferred embodiment comprises an anchoring sleeve underlying thefluid impermeable membrane along at least a distal end portion of thedrive shaft, the fluid impermeable membrane being attached to saidanchoring sleeve proximal to the distal fluid inflatable supportelement.

Preferably, the torque transmitting coil has proximal and distal endsand an anchoring sleeve is disposed around at least a distal end portionof the torque transmitting coil.

Preferably, the torque transmitting coil has proximal and distal endsand the anchoring sleeve extends distally from the distal end of thecoil such that the distal inflatable support element formed around theanchoring sleeve from the fluid impermeable membrane is spaced away fromthe distal end of the torque transmitting coil, the abrasive elementbeing disposed around at least a portion of the circumference of theanchoring sleeve.

In an embodiment with one torque transmitting coil, the anchoring sleevemay extend proximally within and line the torque transmitting coil.

Preferably, the drive shaft comprises inner and outer torquetransmitting coils, the anchoring sleeve being sandwiched between saidinner and outer torque transmitting coils, the anchoring sleeve and theinner torque transmitting coil extending distally from a distal end ofthe outer torque transmitting coil, the abrasive clement being disposedaround at least a portion of the circumference of the anchoring sleeve.

Preferably, the anchoring sleeve is closed at its distal end.

Preferably, the anchoring sleeve has an opening therein associated withthe distal fluid inflatable support element to allow pressurised fluidto flow through said opening into the distal fluid inflatable supportelement from the lumen of the drive shaft.

Preferably, the distal end of the device and the closed distal end ofthe sleeve are spaced away from each other to form a soft atraumaticcushion between the distal end of the device and the closed distal endof the anchoring sleeve.

Preferably, the device comprises an elongate core element advanceablethrough the lumen of the drive shaft to stiffen the drive shaft andwhich assists in the advancement of the drive shaft along the vesseltowards the treatment site.

The elongate core element preferably has a distal end configured foroperational engagement with the distal end of the anchoring sleeve.

Preferably, the elongate core element is configured to be removed fromthe device after the distal end of the device has been advanced to thetreatment site so that a detachable fluid supply tube can be attached tothe device.

The elongate core element preferably includes a lumen for the passage offluid therealong.

Preferably, the elongate core element has at least one opening locatedat or proximal to its distal end, said opening providing fluidcommunication between the lumen of the elongate core element and thelumen of the drive shaft.

The anchoring sleeve is preferably formed from a fluid impermeablemembrane.

Preferably, the anchoring sleeve comprises at least one opening locatedproximal to the closed distal end of the sleeve, said opening providingfluid communication between the lumen of the drive shaft and the distalfluid inflatable support element.

Preferably, the distal fluid inflatable support element has, wheninflated, a centre of mass which lies along the longitudinal axis of thetorque transmitting coil and the lumen of the drive shaft.

Preferably, a fluid inflatable space within the distal fluid inflatablesupport element extends uniformly around the longitudinal axis of thetorque transmitting coil and the lumen of the drive shaft to provide thedistal support element with a centre of mass which lies along thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft when said distal support element is fluid inflated.

Preferably, there is a plurality of openings in the wall of the fluidinflatable distal support element, said openings being located aroundthe circumference of the wall of the fluid inflatable distal supportelement such that, during rotation of the drive shaft, at least some ofsaid openings face an inner surface of a treated vessel, so that flowsof fluid through the openings form a layer of fluid between the outerwall of the fluid inflated distal support element and a wall of thetreated vessel, said layer of fluid forming a fluid bearing between theouter wall of the rotating fluid inflated distal support element and thewall of the treated vessel.

Preferably, the rotational atherectomy device comprises a proximal fluidinflatable support element located proximal to and spaced away from theabrasive element, the proximal fluid inflatable support element havingan outer wall.

Preferably, the outer wall of the proximal fluid inflatable supportelement is continuous and integral with the fluid impermeable membrane.

Preferably, the proximal fluid inflatable support element has, wheninflated, a centre of mass which lies along the longitudinal axis of thetorque transmitting coil and the lumen of the drive shaft.

Preferably, a fluid inflatable space within the proximal fluidinflatable support element extends uniformly around a longitudinal axisof the torque transmitting coil and the lumen of the drive shaft toprovide the proximal support element with a centre of mass which liesalong the longitudinal axis of the torque transmitting coil and thelumen of the drive shaft when said proximal support element is fluidinflated.

Preferably, there is a plurality of openings in the wall of the fluidinflatable proximal support element, said openings being located aroundthe circumference of the wall of the fluid inflatable proximal supportelement such that, during rotation of the drive shaft, at least some ofsaid openings face an inner surface of a treated vessel, so that flowsof fluid through the openings form a layer of fluid between the outerwall of the fluid inflated proximal support element and a wall of thetreated vessel, said layer of fluid forming a fluid bearing between theouter wall of the rotating fluid inflated proximal support element andthe wall of the treated vessel.

Preferably, the abrasive element has a centre of mass which lies on thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft.

In a modified embodiment, the abrasive element may have a centre of masswhich is offset in a radial direction from the longitudinal axis of thetorque transmitting coil and the lumen of the drive shaft.

In an alternative embodiment of the invention, the centre of mass of theabrasive element is always offset in a radial direction from thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft.

In the alternative embodiment, the distal fluid inflatable supportelement has, when inflated, a centre of mass which is offset in a radialdirection from the longitudinal axis of the torque transmitting coil andthe lumen of the drive shaft.

Preferably in the alternative embodiment, the centre of mass of thedistal fluid inflatable support element and the centre of mass of theabrasive element are offset from the longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft in oppositedirections.

In the alternative embodiment, preferably, the wall of the distal fluidinflatable support element is bonded to a segment of a circumference ofthe torque transmitting coil, a middle point of said segment beingspaced from the longitudinal axis of the coil and the lumen of the driveshaft in the same direction as the centre of mass of the abrasiveelement.

In the alternative embodiment, preferably, the wall of the distal fluidinflatable support element defines a fluid inflatable space that extendsonly partially around a circumference of the torque transmitting coil sothat, when the distal inflatable support element is fluid inflated, itscentre of mass is offset from a longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft in one direction, thedistal fluid inflated support element acting, during rotation of thedrive shaft, as a counterweight to the abrasive element which has itscentre of mass offset from the longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft in the oppositedirection.

In the alternative embodiment, the abrasive element preferably has acentre of mass which is offset in a radial direction from thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft, the wall of the distal fluid inflatable support elementdefining a fluid inflatable space that extends only partially around acircumference of the anchoring sleeve so that, when the distalinflatable support element is fluid inflated, its centre of mass isoffset from the longitudinal axis of the torque transmitting coil andthe lumen of the drive shaft in a direction opposite to the direction inwhich the centre of mass of the abrasive element is offset from thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft, the distal fluid inflated support element acting, duringrotation of the drive shaft, as a counterweight to the abrasive element.

Preferably, the alternative embodiment comprises a proximal fluidinflatable support element located proximal to and spaced away from theabrasive element, the proximal fluid inflatable support element havingan outer wall which is bonded to a segment of the circumference of thetorque transmitting coil, a middle point of said segment being spacedfrom the from the longitudinal axis of the torque transmitting coil andthe lumen of the drive shaft in the same direction as the centre of massof the abrasive element.

Preferably, the rotational atherectomy device of the alterativeembodiment comprises a proximal fluid inflatable support element locatedproximal to and spaced away from the abrasive element, the proximalfluid inflatable support element having an outer wall which defines afluid inflatable space that extends only partially around acircumference of the anchoring sleeve so that, when the proximalinflatable support element is fluid inflated, its centre of mass isoffset from a longitudinal axis of the torque transmitting coil and thelumen of the drive shaft in a direction opposite to the direction inwhich the centre of mass of the abrasive element is offset from thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft, the proximal fluid inflated support element acting, duringrotation of the drive shaft, as a counterweight to the abrasive element.

Preferably, in the alternative embodiment, the abrasive element has acentre of mass which is offset in a radial direction from thelongitudinal axis of the torque transmitting coil and lumen of the driveshaft, the walls of the distal and proximal fluid inflatable supportelements defining fluid inflatable spaces that extend only partiallyaround a circumference of the torque transmitting coil so that, when theinflatable support elements are fluid inflated, their centres of massare offset from the longitudinal axis of the torque transmitting coiland the lumen of the drive shaft a direction opposite to the directionin which the centre of mass of the abrasive element is offset from thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft, the fluid inflated support elements acting, during rotationof the drive shaft, as a counterweights to the abrasive element.

Preferably, in the alternative embodiment, the wall of the distal fluidinflatable support element has an outflow opening located such that saidoutflow opening, during rotation of the drive shaft, faces an innersurface of a treated vessel so that fluid flowing through the outflowopening forms a layer of fluid between the outer wall of the rotatingfluid inflated distal support element and a wall of the treated vessel,said layer of fluid forming a fluid bearing between the outer wall ofthe rotating fluid inflated distal support element and the wall of thetreated vessel.

Preferably, in the alternative embodiment, at least a few openings inthe outer wall of a rotating fluid inflated distal support element arelocated around a circumference of the wall of the inflated distalsupport element such that at any time during rotation of the drive shaftat least one of said few openings is facing an inner surface of atreated vessel, so that a flow of fluid through the opening forms alayer of fluid between the wall of the rotating fluid inflated distalsupport element and a wall of the treated vessel, said layer of fluidforming a fluid bearing between the wall of the rotating fluid inflatedsupport element and the wall of the treated vessel.

Preferably, in the alternative embodiment, at least one opening in thewall of a rotating fluid inflated proximal support element is locatedsuch that at any time during rotation of the drive shaft said opening isfacing an inner surface of a treated vessel, so that a flow of fluidthrough the opening forms a layer of fluid between the wall of therotating fluid inflated proximal support element and a wall of thetreated vessel, said layer of fluid forming a fluid bearing between thewall of the rotating fluid inflated proximal support element and thewall of the treated vessel.

Preferably, in the alternative embodiment, at least a few openings inthe outer wall of a rotating fluid inflated proximal support element arelocated around circumference of the wall of the inflated distal supportelement such that at any time during rotation of the drive shaft atleast one of said few openings is facing an inner surface of a treatedvessel, so that a flow of fluid through the opening forms a layer offluid between the wall of the rotating fluid inflated proximal supportelement and a wall of the treated vessel, said layer of fluid forming afluid beating between the wall of the rotating fluid inflated supportelement and the wall of the treated vessel.

Preferably, the walls of both inflatable support elements are made froma continuous stretchable membrane, said fluid impermeable stretchablemembrane being sandwiched between the torque transmitting coil and atleast one non-stretchable sleeve, the non-stretchable sleeve beingdisposed around the stretchable membrane between the fluid inflatablesupport elements. Preferably, the non-stretchable sleeve is formed intwo sections, each section being disposed on either side of the abrasiveelement. Preferably, a second long, non-stretchable sleeve overlaps thestretchable membrane for a short distance proximal to the proximal fluidinflatable support element and extends in a proximal direction aroundthe torque transmitting coil towards the proximal end of the driveshaft. Preferably, the non-stretchable sleeve is fluid impermeable.

Preferably, in the above-described alternative embodiment, the abrasiveelement has a centre of mass which is spaced away from the longitudinalaxis of the torque transmitting coil and the lumen of the drive shaft,and an anchoring sleeve is disposed around the torque transmitting coilat least along a length of the drive shaft occupied by fluid inflatablesupport elements, said anchoring sleeve being disposed over the coilunder the fluid impermeable membrane which forms fluid inflatablesupport elements, the fluid impermeable membrane along a length of thefluid inflatable support elements being bonded to the anchoring sleeveonly along one side of a circumference of the drive shaft, therebypreventing the fluid inflatable support elements from expandinguniformly around an entire circumference of the anchoring sleeve whenfluid inflated so as to form fluid inflated counterweights with centresof mass spaced radially away from a longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft in a directionopposite to the direction in which the centre of mass of the abrasiveelement is spaced away from the longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft.

Preferably, the lumen of the drive shaft has proximal and distalportions, the proximal portion of the the lumen having a largercross-sectional area relative to the cross-sectional area of the distalportion of the lumen so that per unit of length hydraulic resistance tofluid flow of the proximal portion of the lumen is less than thehydraulic resistance to fluid flow of the distal portion of the lumen.

Preferably, all the pressurised fluid which flows through the lumen ofthe drive shaft exits from the device into the vessel through opening(s)in the wall(s) of the fluid inflatable support elements.

Preferably, the abrasive element is spaced away from the distal end ofthe torque transmitting coil.

Preferably, in the rotational aherectoomy device which has inner andouter torque transmitting coils, the abrasive element is spaced awayfrom the distal end of the outer torque transmitting coil.

According to the present invention, there is provided a rotationalatherectomy device for abrading a stenotic lesion from a vessel of apatient comprising a rotatable, flexible drive shaft, a distal fluidinflatable support element located at a distal end of the device and anabrasive element mounted to the drive shaft proximal to and spaced awayfrom the distal fluid inflatable support element, both the abrasiveelement and the distal fluid inflatable support element being rotatabletogether with the drive shaft, the drive shaft comprising a torquetransmitting coil which defines a long lumen of the drive shaft, thedistal fluid inflatable support element being formed from a fluidimpermeable membrane that crosses a longitudinal axis common to thetorque transmitting coil and the lumen of the drive shaft at the distalend of the device, thereby preventing pressurized fluid flowing alongthe lumen of the drive shaft from entering the vessel in the directionof said longitudinal axis so that fluid has to pass through the fluidinflatable support element, inflating said support element and exitingfrom the device through an outflow opening in the fluid inflatablesupport element in a direction different from the direction of thelongitudinal axis of the coil and the lumen.

In one preferred embodiment, the abrasive element has a centre of masswhich is offset in a radial direction from the longitudinal axis of thecoil and the lumen of the drive shaft. In another preferred embodiment,the abrasive element has a centre of mass which lies on the longitudinalaxis of the coil and the lumen of the drive shaft.

The fluid impermeable membrane preferably extends around and is bondedto a surface of the torque transmitting coil proximal to the distalfluid inflatable support element.

The wall of the distal fluid inflatable support element preferablyextends around the torque transmitting coil of the drive shaft.

In one preferred embodiment, the wall of the distal fluid inflatablesupport element is bonded to a segment of the circumference of thetorque transmitting coil, a middle point of said segment being spacedfrom the longitudinal axis of the coil and the lumen of the drive shaftin the same direction as the centre of mass of the abrasive element.

The torque transmitting coil preferably comprises at least one spacewhich separates individual windings of the coil, said space allowingfluid communication between the lumen of the drive shaft and the distalfluid inflatable support element.

One preferred embodiment comprises an anchoring sleeve underlying thefluid impermeable membrane along at least a distal end portion of thedrive shaft, the fluid impermeable membrane being attached to saidanchoring sleeve proximal to the distal fluid inflatable supportelement.

In one preferred embodiment, the torque transmitting coil has proximaland distal ends and the anchoring sleeve is disposed around at least adistal end portion of the torque transmitting coil.

Preferably, the torque transmitting coil has proximal and distal endsand the anchoring sleeve extends distally from the distal end of thecoil such that the distal fluid inflatable support element formed aroundthe anchoring sleeve from the fluid impermeable membrane is spaced awayfrom the distal end of the torque transmitting coil and disposed(located) around at least a portion of the circumference of theanchoring sleeve.

The anchoring sleeve may extend proximally within and line the torquetransmitting coil.

In a preferred embodiment, the drive shaft comprises inner and outertorque transmitting coils, the anchoring sleeve being sandwiched betweensaid inner and outer torque transmitting coils, the anchoring sleeve andthe inner torque transmitting coil extending distally from the distalend of the outer torque transmitting coil, the abrasive element beinglocated around at least a portion of the circumference of the anchoringsleeve and being spaced away from the distal end of the outer torquetransmitting coil.

In one embodiment, the anchoring sleeve may be closed at its distal end.In one embodiment, the anchoring sleeve may have an opening thereinassociated with the distal fluid inflatable support element to allowpressurised fluid to flow through said opening into the distal fluidinflatable support element from the lumen of the drive shaft.

The distal end of the device may be closed by the fluid impermeablemembrane and spaced in a longitudinal direction from the closed distalend of the anchoring sleeve to form a soft atraumatic cushion at thedistal end of the device.

One preferred embodiment of the invention may comprise an elongate coreelement advanceable through the lumen of the drive shaft to stiffen thedrive shaft and thereby assist in the advancement of the drive shaftalong the vessel towards the treatment site.

The elongate core element may have a distal end configured foroperational engagement with the distal end of the anchoring sleeve.

The elongate core element may be configured to be removed from thedevice after the distal end of the device has been advanced to thetreatment site so that a detachable fluid supply tube can be attached tothe device.

In one preferred embodiment, the elongate core element includes a lumenfor the passage of fluid therealong, the elongate core elementpreferably having at least one opening located at or proximal to itsdistal end, said opening providing fluid communication between the lumenof the elongate core element and the lumen of the drive shaft.

The elongate core element may have a coil at its distal end, and theelongate core element may be a coil.

Preferably, the anchoring sleeve is formed from a fluid impermeablemembrane.

The anchoring sleeve may comprise at least one opening located proximalto the closed distal end of the sleeve, said opening providing fluidcommunication between the lumen of the drive shaft and the distal fluidinflatable support element.

In a preferred embodiment, the device comprises a proximal fluidinflatable support element located proximal to and spaced away from theabrasive element, the proximal fluid inflatable support element havingan outer wall.

In one preferred embodiment, the outer wall of the proximal fluidinflatable support element is continuous and integral with the fluidimpermeable membrane.

The wall of the proximal fluid inflatable support element may be bondedto a segment of the circumference of the torque transmitting coil, amiddle point of said segment being spaced from the longitudinal axis ofthe drive shaft in the same direction as the centre of mass of theabrasive element.

The torque transmitting coil may comprise at least one space whichseparates individual windings of the coil, said space allowing fluidcommunication between the lumen of the drive shaft and the proximalfluid inflatable support element.

The anchoring sleeve may have an opening therein associated with theproximal fluid inflatable support element to allow pressurised fluid toflow through said opening into the proximal fluid inflatable supportelement from the lumen of the drive shaft.

In one preferred embodiment, all of the pressurised fluid which flowsthrough the lumen of the drive shaft exits from the device into thevessel through opening(s) in the wall(s) of the fluid inflatable supportelements.

The distal fluid inflatable support element may have, when inflated, acentre of mass which is offset in a radial direction from thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft.

The centre of mass of the distal fluid inflatable support element andthe centre of mass of the abrasive element may be offset from thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft in diametrically opposite directions.

In one preferred embodiment, the wall of the distal fluid inflatablesupport element defines a fluid inflatable space that extends onlypartially around a circumference of the torque transmitting coil sothat, when the distal inflatable support element is fluid inflated, itscentre of mass is offset from a longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft in one direction, thedistal fluid inflated support element acting, during rotation of thedrive shaft, as a counterweight to the abrasive element which has itscentre of mass offset from the longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft in the oppositedirection.

In one preferred embodiment, the wall of the distal fluid inflatablesupport element defines a fluid inflatable space that extends onlypartially around a circumference of the anchoring sleeve so that, whenthe distal inflatable support element is fluid inflated, its centre ofmass is offset from a longitudinal axis of the torque transmitting coiland the lumen of the drive shaft in one direction, the distal fluidinflated support element acting, during rotation of the drive shaft, asa counterweight to the abrasive element which has its centre of massoffset from the longitudinal axis of the torque transmitting coil andthe lumen of the drive shaft in the opposite direction.

The proximal fluid inflatable support element may have, when inflated, acentre of mass which is offset in a radial direction from thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft.

The centre of mass of the proximal fluid inflatable support element andthe centre of mass of the abrasive element may be offset from thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft in diametrically opposite directions.

In one preferred embodiment, the wall of the proximal fluid inflatablesupport element defines a fluid inflatable space that extends onlypartially around a circumference of the torque transmitting coil sothat, when the proximal inflatable support element is fluid inflated,its centre of mass is offset from a longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft in one direction, thedistal fluid inflated support element acting, during rotation of thedrive shaft, as a counterweight to the abrasive element which has itscentre of mass offset from the longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft in the oppositedirection.

In another preferred embodiment, fluid inflatable spaces within both thedistal and proximal fluid inflatable support elements extend radiallyaway from the longitudinal axis of the torque transmitting coil and thelumen of the drive shaft in a direction diametrically opposite to thedirection in which the center of mass of the abrasive element is spacedaway from the longitudinal axis of the torque transmitting coil and thelumen of the drive shaft.

In another preferred embodiment, the distal fluid inflatable supportelement may have, when inflated, a centre of mass which lies along thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft.

Preferably, in this preferred embodiment, a fluid inflatable spacewithin the distal fluid inflatable support element extends uniformlyaround an entire circumference of the drive shaft, providing the distalsupport element with a centre of mass which lies along the longitudinalaxis of the torque transmitting coil and the lumen of the drive shaftwhen said distal support element is fluid inflated.

The proximal fluid inflatable support element may also have, wheninflated, a centre of mass which lies along the longitudinal axis of thetorque transmitting coil and the lumen of the drive shaft.

In a preferred embodiment, a fluid inflatable space within the proximalfluid inflatable support element extends uniformly around a longitudinalaxis of the torque transmitting coil and the lumen of the drive shaft,therefore providing a fluid inflated proximal support element with acentre of mass which lies along the longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft when the proximalsupport element is fluid inflated.

In a preferred embodiment, the wall of the distal fluid inflatablesupport element has an outflow opening located such that said outflowopening, during rotation of the drive shaft, faces an inner surface of atreated vessel so that fluid flowing through the outflow opening forms alayer of fluid between the outer wall of the rotating fluid inflateddistal support element and a wall of the treated vessel, said layer offluid forming a fluid bearing between the outer wall of the rotatingfluid inflated distal support element and the wall of the treatedvessel.

In a preferred embodiment, at least a few openings in the outer wall ofa rotating fluid inflated distal support element are located aroundcircumference of the wall of the inflated distal support element suchthat at any time during rotation of the drive shaft at least one of saidfew openings is facing an inner surface of a treated vessel, so that aflow of fluid through the opening forms a layer of fluid between thewall of the rotating fluid inflated distal support element and a wall ofthe treated vessel, said layer of fluid forming a fluid bearing betweenthe wall of the rotating fluid inflated support element and the wall ofthe treated vessel.

In a preferred embodiment, at least one opening in the wall of arotating fluid inflated proximal support element is located such that atany time during rotation of the drive shaft said opening is facing aninner surface of a treated vessel, so that a flow of fluid through theopening forms a layer of fluid between the wall of the rotating fluidinflated proximal support element and a wall of the treated vessel, saidlayer of fluid forming a fluid bearing between the wall of the rotatingfluid inflated proximal support element and the wall of the treatedvessel.

There may be a plurality of openings in the wall of the fluid inflatableproximal support element, said openings being located around thecircumference of the wall of the fluid inflatable proximal supportelement such that, during rotation of the drive shaft, at least some ofsaid openings face an inner surface of a treated vessel, so that flowsof fluid through the openings form a layer of fluid between the outerwall of the fluid inflated proximal support element and a wall of thetreated vessel, said layer of fluid forming a fluid bearing between theouter wall of the rotating fluid inflated proximal support element andthe wall of the treated vessel.

In one preferred embodiment, there is a plurality of openings in thewall of the fluid inflatable distal support element, said openings beinglocated around the circumference of the wall of the fluid inflatabledistal support element such that, during rotation of the drive shaft, atleast some of said openings face an inner surface of a treated vessel,so that flows of fluid through the openings form a layer of fluidbetween the outer wall of the fluid inflated distal support element anda wall of the treated vessel, said layer of fluid forming a fluidbearing between the outer wall of the rotating fluid inflated distalsupport element and the wall of the treated vessel.

The walls of both inflatable support elements may be made from acontinuous stretchable membrane, said fluid impermeable stretchablemembrane being sandwiched between the torque transmitting coil and atleast one non-stretchable sleeve, the non-stretchable sleeve beingdisposed around the stretchable membrane between the fluid inflatablesupport elements. This non-stretchable sleeve may be formed in twosections, each section being disposed on either side of the abrasiveelement.

A second long, non-stretchable sleeve preferably overlaps thestretchable membrane for a short distance proximal to the proximal fluidinflatable support element and extends in a proximal direction aroundthe torque transmitting coil towards the proximal end of the driveshaft. This non-stretchable sleeve is preferably fluid impermeable.

An anchoring sleeve may be disposed around the torque transmitting coilat least along a length of the drive shaft occupied by fluid inflatablesupport elements , said anchoring sleeve being disposed over the coilunder the fluid impermeable membrane which forms the distal fluidinflatable support element, the fluid impermeable membrane along alength of the fluid inflatable support elements being bonded to theanchoring sleeve only along one side of a circumference of the driveshaft, thereby preventing the fluid inflatable support elements fromexpanding uniformly around an entire circumference of the anchoringsleeve when fluid inflated so as to form a fluid inflated counterweightswith centres of mass spaced radially away from a longitudinal axis ofthe torque transmitting coil and the lumen of the drive shaft in adirection opposite to the direction in which a centre of mass of theabrasive element is spaced away from the longitudinal axis of the torquetransmitting coil and the lumen of the drive shaft.

The lumen of the drive shaft may have proximal and distal portions, theproximal portion of the the lumen having a larger cross-sectional arearelative to the cross-sectional area of the distal portion of the lumenso that per unit of length hydraulic resistance to fluid flow of theproximal portion of the lumen is less than the hydraulic resistance tofluid flow of the distal portion of the lumen.

Reference is made to “distal” and “proximal” ends and to flow of fluidin an “antegrade” and “retrograde” direction. For the avoidance ofdoubt, and for the purpose of this specification, the distal end isconsidered to refer to the end of the device which is inserted into thevessel in the body of the patient and the proximal end is the end of thedevice which remains outside the body of the patient and is connected toan advancing and rotational drive assembly. The term ‘antegrade flow’refers to a direction of fluid flow from the proximal to the distal endof the device. Similarly, the term ‘retrograde flow’ refers to a fluidflow in the opposite direction, i.e. from the distal to the proximal endof the device. The antegrade flowing fluid is indicated by arrows ‘FF’in the drawings. The retrograde flowing fluid is indicated by arrows‘RF’ in the drawings. Embolic particles are marked as ‘EP’ in thedrawings.

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying drawings, in which:

FIG. 1 is a longitudinal cross-sectional view of a distal end portion ofa rotational atherectomy device according to a first embodiment of theinvention. The device comprises a rotatable drive shaft, an abrasiveelement mounted to the drive shaft proximal to its distal end and, apair of fluid inflatable support elements. The fluid inflatable supportelements are located distal and proximal to the abrasive element. Theabrasive element and the fluid inflatable support elements are rotatabletogether with the drive shaft. The drive shaft comprises a torquetransmitting coil and a long lumen having a fluid impermeable wall andconfigured for transfer of pressurized fluid towards the distal end ofthe drive shaft. The long lumen of the drive shaft is coaxial with thetorque transmitting coil and is in fluid communication with both fluidinflatable support elements. The distal fluid inflatable support elementis formed from a fluid impermeable membrane that crosses a longitudinalaxis of the lumen of the drive shaft (and of the torque transmittingcoil) at a distal end of the device.

FIG. 2 shows the device of FIG. 1 after the flow of pressurized fluidalong the lumen the drive shaft has been initiated and the supportelements have been inflated by said flow of pressurized fluid. FIG. 2illustrates that the fluid impermeable membrane prevents pressurizedfluid flowing along the lumen of the drive shaft from entering thevessel in the direction of the longitudinal axis of the lumen (and thecoil). FIG. 2 illustrates that the pressurized fluid has to pass throughthe fluid inflatable support elements and inflate them. The pressurizedfluid exits from the device through outflow openings in the fluidinflated support elements. The pressurized fluid exits through theoutflow openings in directions which ate different from the direction ofthe longitudinal axis of the coil and the lumen.

FIG. 3 shows a cross-section through A1 ¹-A1 ¹ of FIG. 1;

FIG. 4 shows a cross-section through A1 ¹¹-A1 ¹¹ of FIG. 1;

FIG. 5 shows a cross-section through A1 ¹¹¹-A1 ¹¹¹ of FIG. 1;

FIG. 6 shows a cross-section through A3 ¹-A3 ¹ of FIG. 2. FIG. 6illustrates that a fluid inflatable space within the distal supportelements extends only partially around a circumference of the torquetransmitting coil;

FIG. 7 shows a cross-section through A3 ¹¹-A3 ¹¹ of FIG. 2;

FIG. 8 shows a cross-section through A3 ¹¹¹-A3 ¹¹¹ of FIG. 2. FIG. 8illustrates that a fluid inflatable space within the proximal supportelements extends only partially around a circumference of the torquetransmitting coil;

FIG. 9 is a longitudinal cross-sectional view of a distal end portion ofa rotational atherectomy device according to a second embodiment of theinvention, the device comprising an anchoring sleeve which is underlyingthe fluid impermeable membrane along a distal end portion of the torquetransmitting coil. The walls of the fluid inflatable support elementsare bonded only to segments of the circumference of the anchoringsleeve, said segments of the anchoring sleeve being located such that amiddle point of each segment is spaced from the longitudinal axis of thetorque transmitting coil in the same direction as a centre of a mass ofthe abrasive element. The abrasive element extends around the anchoringsleeve and has a center of mass spaced away from the longitudinal axisof the drive shaft;

FIG. 10 shows the device of FIG. 9 after the flow of pressurized fluidalong the lumen the drive shaft has been initiated. FIG. 10 illustratesthat the pattern of fluid flow through the device is similar to thatshown in FIG. 2 of the first embodiment. The support elements areinflated by the pressurized fluid that flows into the inflatable supportelements through apertures in the anchoring sleeve.

FIG. 11 shows a longitudinal cross-sectional view of a distal endportion of a first modification of the second embodiment of theinvention. FIG. 11 shows the first modification in which the abrasiveelement is bonded by a longitudinally extending strap to the outersurface of the fluid impermeable membrane. In the modified embodiment ofFIG. 11, the fluid impermeable membrane forms the walls of both fluidinflatable support elements, but does not extend around a proximal endportion of the torque transmitting coil. The anchoring sleeve extendsproximally around the torque transmitting coil towards the proximal endof the drive shaft. The anchoring sleeve forms the wall of the lumen ofthe drive shaft and therefore should be made from a fluid impermeablematerial.

FIG. 12 shows the device of FIG. 11 after the flow of pressurized fluidalong the lumen the drive shaft has been initiated. FIG. 12 illustratesthat the pattern of fluid flow through the device is similar to thatshown in FIG. 2 of the first embodiment.

FIG. 13 shows a cross-section through B1 ¹-B1 ¹ of FIG. 11;

FIG. 14 shows a cross-section through B1 ¹¹-B¹¹ of FIG. 11;

FIG. 15 shows a cross-section through B1 ¹¹¹-B¹¹¹ of FIG. 11;

FIG. 16 shows a cross-section through B3 ¹-B3 ¹ of FIG. 12. FIG. 16illustrates that a fluid inflatable space within the distal supportelements extends only partially around a circumference of the anchoringsleeve;

FIG. 17 shows a cross-section through B3 ¹¹-B3 ¹¹ of FIG. 12;

FIG. 18 shows a cross-section through B3 ¹¹¹-B3 ¹¹¹ of FIG. 12. FIG. 18illustrates that a fluid inflatable space within the proximal supportelements extends only partially around a circumference of the anchoringsleeve

FIG. 19 shows a second modification of the second embodiment of thedevice of the invention. FIG. 19 shows the device which is similar tothe device shown in FIG. 11, but in which the anchoring sleeve extendsonly around a distal end portion of the the torque transmitting coil.The fluid impermeable membrane forms walls of the inflatable supportelements around the distal end potion of the torque transmitting coiland extends in a proximal direction around the torque transmitting coiltowards the proximal end of the drive shaft;

FIG. 20 shows the device of FIG. 19 after an antegrade flow of fluid hasbeen initiated. FIG. 20 illustrates that the pattern of fluid flowthrough the device is similar to that shown in FIG. 2 of the firstembodiment and FIG. 12 of the first modification of the secondembodiment;

FIG. 21 shows a third modification of the second embodiment of thedevice of the invention. FIG. 21 shows the device which is similar tothe device shown in FIG. 11, but in which the anchoring sleeve is closedat its distal end. The device shown in FIG. 21 also differs from thedevice shown in FIG. 11 in that the closed distal end of the anchoringsleeve is spaced in the longitudinal direction from the distal end ofthe device, the distal end of the device being closed by the membrane sothat the space between the closed end of the anchoring sleeve and theclosed end of the device form a soft atraumatic cushion at the distalend of the device. The device shown in FIG. 21 also differs from thedevice shown in FIG. 11 in that the anchoring sleeve extends distallyfrom a distal end of the torque transmitting coil such that theinflatable support elements are spaced away from the distal end of thetorque transmitting coil. Yet another difference between the second andthird modifications of the second embodiment is that the abrasiveelement shown in FIG. 21 is attached to the membrane by a flexible strapwhich extends around the membrane in FIG. 21 and not along it as shownin FIG. 11;

FIG. 22 shows the device of FIG. 21 after an antegrade flow ofpressurized fluid through the device has been initiated. The supportelements are inflated by the pressurized fluid that flows into theinflatable support elements through apertures in the anchoring sleeve.FIG. 22 illustrates that the pattern of fluid flow through the device issimilar to that shown in FIG. 2 of the first embodiment and FIGS. 12 and20 of the first and second modifications of the second embodiment;

FIG. 23 shows a fourth modification of the second embodiment of thedevice of the invention. The fourth modification of FIG. 23 is similarto the third modification of the second embodiment of FIG. 21, butdiffers in that the centres of mass of the inflatable support elementsare laying along the longitudinal axis of the torque transmitting coiland of the lumen of the drive shaft;

FIG. 24 shows the device of FIG. 23 after an antegrade flow of fluid hasbeen initiated and the support elements have been inflated. FIG. 24illustrates that fluid inflatable spaces within the support elementsextend uniformly around the longitudinal axis of the torque transmittingcoil and the lumen of the drive shaft, therefore providing the fluidinflated support elements with centres of mass which are laying alongthe longitudinal axis of the torque transmitting coil and the lumen ofthe drive shaft, when the support elements are fluid inflated. FIG. 24illustrates that the pattern of fluid flow through the device is similarto that shown in FIG. 2 of the first embodiment and FIGS. 12, 20 and 22of the first, second and third modifications of the second embodiment.The pressurized fluid is exiting from the device through the outflowopenings located around the entire circumference of the inflated supportelements;

FIG. 25 shows a fifth modification of the second embodiment of thedevice of the invention. The embodiment of FIG. 25 is similar to thefourth modification of the second embodiment shown in FIG. 23, butdiffers in that the drive shaft comprises inner and outer torquetransmitting coils. The anchoring sleeve is sandwiched between the innerand outer torque transmitting coils. The anchoring sleeve and the innertorque transmitting coil extend distally from the distal end of theouter torque transmitting coil such that the inflatable support elementsformed around the anchoring sleeve from the fluid impermeable membraneare spaced away from the distal end of the outer torque transmittingcoil;

FIG. 26 shows the device of FIG. 25 after an antegrade flow of fluid hasbeen initiated and the support elements have been inflated. FIG. 26illustrates that the pattern of fluid flow through the device is similarto that shown in FIG. 24 of the fourth modification of the secondembodiment;

FIG. 27 is a side sectional view of a portion of a blood vessel having astenotic lesion. FIG. 27 illustrates the rotational device of a sixthmodification of the second embodiment of the invention which has beenadvanced across the stenotic lesion to a position in which the distalfluid inflatable support element is located distal to the stenoticlesion and the proximal fluid inflatable support element isintentionally located proximal to the stenotic lesion to be treated. Thedevice of

FIG. 27 is similar to the device of the third modification of the secondembodiment of FIG. 21, but differs in that it comprises an elongate coreelement disposed in the lumen of the drive shaft to stiffen the driveshaft and thereby assist in the advancement of the device along thevessel towards and across the stenotic lesion;

FIG. 28 shows the same view as FIG. 27 but with the core element beingpartially withdrawn from the lumen of the drive shaft;

FIG. 29 shows the same view as FIGS. 27 and 28, but with the coreelement completely removed from the lumen of the drive shaft. It shouldbe noted that the core element should be removed completely from therest of the device to allow attachment of a detachable fluid supply tubeto the device;

FIG. 30 shows the same view as FIG. 29 but after a flow of pressurizedfluid has been initiated in an antegrade direction along the lumen ofthe drive shaft and through the openings in the anchoring sleeve intothe inflatable support elements to inflate said support elements. Thepressurized fluid flowing along the lumen of the drive shaft is enteringthe treated vessel only through the openings in the walls of theinflatable support elements;

FIGS. 31 through 36 illustrate abrading of the stenotic lesion by therotating abrasive element and formation of fluid bearings between theinner surface of the vessel and the walls of the rotating fluid inflatedsupport elements, said fluid bearings being formed by flow of fluidthrough the openings in the walls of the fluid inflated supportelements;

FIG. 37 shows the distal end section of the device after rotation of thedevice has been stopped but prior to stopping the flow of pressurizedfluid along the lumen of the drive shaft.

FIG. 38 shows the distal end portion of the device after the flow ofpressurized fluid along the lumen of the drive shaft has been stopped;

FIGS. 39 and 40 illustrate the removal of the device from the treatedvessel and appearance of the treated vessel after removal of the device;

FIG. 41 shows a seventh modification of the second embodiment of thedevice of the invention. The device shown FIG. 41 is similar to thedevice shown in FIG. 27, but differs in that the core element comprisesa long lumen, said lumen being in fluid communication with the lumen ofthe drive shaft through an opening located in a wall of the core elementadjacent to its distal end;

FIG. 42 shows the device of FIG. 41 in which pressurized fluid isflowing from the lumen of the core element into the lumen of the driveshaft;

FIG. 43 shows the device of FIG. 42 in which the core element is beingwithdrawn from the lumen of the drive shaft and the device. Thecontinuous flow of the pressurized fluid from the lumen of the coreelement into the lumen of the drive shaft is assisting in removing thecore element from the lumen of the drive shaft without changing positionof the device in the treated vessel;

FIG. 44 shows the device of FIGS. 42 and 43 except that the pressurizedfluid has been pumped from the lumen of the core element into the lumenof the drive shaft at such a combination of fluid pressure and fluidflow rates which caused the distal inflatable support element(counterweight) to become sufficiently distended to become anchoreddistal to or against the stenotic lesion to be treated.

FIG. 45 shows that the anchoring the distal fluid inflatable supportelement either distal to or against the stenotic lesion to be treatedmay help in removing the core element from the lumen of the drive shaftwithout changing the position of the device in the vessel to be treated.

FIG. 46 shows a longitudinal cross-sectional view of a distal endportion of a third embodiment of the device of the invention. In thisembodiment the inflatable support elements are formed from a fluidimpermeable stretchable membrane. The stretchable membrane proximal tothe distal fluid inflatable support element is sandwiched between thetorque transmitting coil and a non-stretchable sleeve. Anothernon-stretchable, fluid impermeable sleeve extends around a proximal endportion of the stretchable membrane and further around the torquetransmitting coil towards the proximal end of the drive shaft;

FIG. 47 shows one modification of the third embodiment of the device ofthe invention. This embodiment is similar to that shown in FIG. 44, butdiffers in that the non-stretchable sleeve is comprised of two segments,one segment being disposed around the stretchable membrane between theabrasive element and the distal fluid inflatable support element and theother between the abrasive element and the proximal fluid inflatablesupport element.;

FIG. 48 shows the device of FIG. 47 after an antegrade flow of fluid hasbeen initiated and the support elements have been inflated. FIG. 48illustrates that the pattern of fluid flow through the device is similarto that shown in FIG. 26 of the fifth modification of the secondembodiment;

FIG. 49 illustrates a fourth embodiment of the device. FIG. 49 shows thedevice after the antegrade flow of pressurized fluid has been initiatedand the support elements have been inflated. The device of FIG. 49 issimilar to the device of the third modification of the second embodimentof the device shown in FIG. 22, but differs in that the lumen of thedrive shaft has proximal and distal portions. The proximal portion ofthe the lumen has a larger cross-sectional area relative to thecross-sectional area of the distal portion of the lumen so that, perunit of length, hydraulic resistance to fluid flow of the proximalportion of the lumen is less than the hydraulic resistance to fluid flowof the distal portion of the lumen.

In FIGS. 1 to 49, the direction of movement of the atherectomy device isindicated by arrow marked “DM”, flow of fluid in an antegrade directionthrough the atherectomy device is indicated by arrows “FF” and flow offluid around the device and across a stenotic lesion in a retrogradedirection is indicated by arrows marked “RF”. Embolic particles abradedfrom the stenotic lesion are indicated as “EP”. Embolic particles EPabraded from the stenotic lesion are entrained by the retrograde flowingfluid RF and aspirated into a drainage lumen formed between therotatable drive shaft and a stationary drive shaft sheath 900.Alternatively, embolic particles EP may be aspirated into a drainagelumen of a separate drainage catheter (not shown). Embolic particles EPare removed from the treated vessel and out of the patient's body.

FIGS. 1 through 8 illustrate in longitudinal and transversecross-sections a distal end portion of the first embodiment of therotational atherectomy device of the invention. The rotationalatherectomy device is comprised of a rotatable, flexible drive shaft 1,a distal fluid inflatable support element 3 located at a distal end 4 ofthe device and an abrasive element 5 mounted to the drive shaft 1proximal to and spaced away from the distal fluid inflatable supportelement 3. The drive shaft 1 comprises a torque transmitting coil 2. Theabrasive element 5 and the distal fluid inflatable support element 3 arerotatable together with the drive shaft 1. The drive shaft 1 includes along lumen 6 for the transport of pressurized fluid to the distal fluidinflatable support element 3. In FIGS. 1 to 8, a wall 7 of the distalfluid inflatable support element 3 and a wall 8 of the long lumen 6 ofthe drive shaft 1 are formed from a single fluid impermeable membrane 9.The fluid impermeable membrane 9 extends around the torque transmittingcoil 2. The torque transmitting coil 2, the long lumen 6 of the driveshaft 1 and the drive shaft 1 itself have common longitudinal axis X-X.The fluid impermeable membrane 9 crosses the longitudinal axis X-X atthe distal end 4 of the device, thereby preventing pressurized fluidflowing along the lumen 6 of the drive shaft 1 from entering the treatedvessel in the direction of said longitudinal axis X-X. Therefore, thepressurized fluid has to pass through and inflate the distal fluidinflatable support element 3, prior to exiting from the device throughoutflow openings 66 in the distal fluid inflatable support element 3 ina direction different from the direction of the longitudinal axis X-X ofthe torque transmitting coil 2 and the lumen 6 of the drive shaft 1.

Preferably, the device comprises a proximal fluid inflatable supportelement 23 located proximal to and spaced away from the abrasive element5. FIGS. 1 and 2 illustrate that a wall 27 of the proximal fluidinflatable support element 23 is continuous and integral with the fluidimpermeable membrane 9 which forms the wall 7 of the distal fluidinflatable support element 3. FIG. 2 also illustrates that thepressurized fluid is passing through and inflating the proximal fluidinflatable support element 23, prior to exiting from the device throughoutflow openings 99 in the proximal fluid inflatable support element 23.

FIGS. 2, 6 and 7 illustrate best that the wall 7 of the distal fluidinflatable support element 3 is bonded only to a segment of thecircumference of the torque transmitting coil 2, said segment of thecoil 2 being located such that a middle point MP_(D) of the segment isspaced from the longitudinal axis X-X of the torque transmitting coil 2in the same direction as a centre of a mass of the abrasive element 5.

FIGS. 2, 7 and 8 illustrate best that the wall 27 of the proximal fluidinflatable support element 23 is also bonded only to a segment of thecircumference of the torque transmitting coil 2, said segment of thecoil 2 being located such that a middle point MP_(P) of the segment isspaced from the longitudinal axis X-X of the torque transmitting coil 2in the same direction as a centre of a mass of the abrasive element 5.

FIGS. 2 and 6 illustrate best that the wall 7 of the distal fluidinflatable support element 3 defines a fluid inflatable space 50 thatextends only partially around the circumference the torque transmittingcoil 2 so that, when the distal inflatable support element 3 is fluidinflated, its centre of mass CM_(DC) is offset from the longitudinalaxis X-X of the torque transmitting coil 2 and the lumen 6 of the driveshaft 1 in one direction, the distal fluid inflated support element 3acting, during rotation of the drive shaft 1, as a counterweight to theabrasive element 5 which has its centre of mass offset from thelongitudinal axis X-X of the torque transmitting coil 2 and the lumen 6of the drive shaft 1 in the opposite direction.

FIGS. 2 and 6 illustrate best that the wall 7of the distal fluidinflatable support element 3 defines a fluid inflatable space 50 thatextends only partially around the circumference the torque transmittingcoil 2 so that, when the distal inflatable support element 3 is fluidinflated, its centre of mass CM_(DC) is offset from the longitudinalaxis X-X of the torque transmitting coil 2 and the lumen 6 of the driveshaft 1 in one direction, the distal fluid inflated support element 3acting, during rotation of the drive shaft 1, as a counterweight to theabrasive element 5 which has its centre of mass offset from thelongitudinal axis X-X of the torque transmitting coil 2 and the lumen 6of the drive shaft 1 in the opposite direction.

FIGS. 2 and 8 illustrate best that the wall 27 of the proximal fluidinflatable support element 23 defines a fluid inflatable space 70 thatextends only partially around the circumference the torque transmittingcoil 2 so that, when the proximal inflatable support element 23 is fluidinflated, its centre of mass CM_(PC) is offset from the longitudinalaxis X-X of the torque transmitting coil 2 and the lumen 6 of the driveshaft 1 in one direction, the proximal fluid inflated support element 23acting, during rotation of the drive shaft 1, as a counterweight to theabrasive element 5 which has its centre of mass offset from thelongitudinal axis X-X of the torque transmitting coil 2 and the lumen 6of the drive shaft 1 in the opposite direction.

FIGS. 9 to 20 illustrate an anchoring sleeve 15 which is open at itsdistal end 18. The anchoring sleeve 15 extends around the torquetransmitting coil 2. The anchoring sleeve 15 is underlying the fluidimpermeable membrane 9 along a distal end portion 20 of the drive shaft1. FIGS. 9 to 20 illustrate that the open distal end 18 of the anchoringsleeve 15 coincides with the distal end 12 of the torque transmittingcoil 2. It should be noted that the device may be constructed with thedistal end 12 of the torque transmitting coil 2 positioned proximal toand spaced away from the distal end 18 of the anchoring sleeve 15.

FIGS. 9 and 10 illustrate that the fluid impermeable membrane 9 isattached or bonded to the anchoring sleeve 15 around its entirecircumference proximal to the distal fluid inflatable support element 3.FIGS. 9 and 10 also illustrate the separate fluid impermeable membrane29, which forms the wall 27′ of the proximal fluid inflatable supportelement 23. The fluid impermeable membrane 29 is attached or bonded tothe anchoring sleeve 15 around its entire circumference both distal andproximal to the proximal fluid inflatable support element 23.

FIGS. 11 to 18 illustrate the first modification of the secondembodiment of the device in which the anchoring sleeve 15 extends in aproximal direction towards the proximal end of the drive shaft 1. Theanchoring sleeve 15 forms the wall of the lumen 6 of the drive shaft 1and therefore should be made from a fluid impermeable material.

FIGS. 19 and 20 illustrate a second modification of the secondembodiment of the device in which the anchoring sleeve 15 extends aroundthe torque transmitting coil 2 only along a distal end portion 20 of thedrive shaft 1. The fluid impermeable membrane 9 extends from the distalend of the device towards the proximal end of the drive shaft 1. FIGS.19 and 20 show that the fluid impermeable membrane 9 may alone form thewall of the lumen 6 of the drive shaft 1 proximal to a proximal end 30of the anchoring sleeve 15.

FIGS. 1 to 20 illustrate the embodiments of the device in which thedistal end of the drive shaft 1 coincides with the distal end 12 of thetorque transmitting coil 2. The proximal ends of the drive shaft 1 andthe torque transmitting coil 2 are not shown in the drawings, but itshould be noted that the torque transmitting coil 2 does not have toextend proximally along the entire length of the drive shaft 1.

FIGS. 21 to 48 illustrate embodiments of the device in which theanchoring sleeve 15′ is closed at its distal end. In these exemplaryembodiments, the distal end of the lumen 6 of the drive shaft 1coincides with the distal end 18′ of the anchoring sleeve 15′. In theseembodiments, the closed distal end 18′ of the anchoring sleeve 15′ isspaced in the longitudinal direction from the distal end 4 of thedevice, the distal end 4 of the device being closed by the membrane 9 sothat a soft atraumatic cushion is formed between the closed end 18′ ofthe anchoring sleeve 15′ and the closed end 4 of the device. In all ofthese embodiments, the support elements are inflated by the pressurizedfluid that flows from the lumen 6 of the drive shaft 1 into theinflatable support elements 3, 23 only through apertures 41, 42 locatedproximal to the closed distal end 18′ of the anchoring sleeve 15′.

FIGS. 21 to 24 illustrate third and fourth modifications of the secondembodiment of the device in which the torque transmitting coil 2 doesnot extend under the fluid inflatable support elements 3, 23. TheseFigures show that the anchoring sleeve 15′ lines the torque transmittingcoil 2 and extends distally from a distal end 12′ of the torquetransmitting coil 2 such that the inflatable support elements 3, 23 arespaced away from the distal end 12′ of the torque transmitting coil 2.These embodiments show that the abrasive element 5 is attached to themembrane 9 by a flexible strap 11 which extends around the membrane 9.It should be noted that the abrasive element itself may extend aroundthe entire circumference of the membrane 9 or the anchoring sleeve 15′,therefore making the strap unnecessary in this and other embodiments ofthe invention.

FIG. 22 illustrates best the third modification of the second embodimentof the device in which the wall 7of the distal fluid inflatable supportelement 3 defines a fluid inflatable space 50′ that extends onlypartially around a circumference of the anchoring sleeve 15′ so that,when the distal inflatable support element 3 is fluid inflated, itscentre of mass CM_(DC) is offset from the longitudinal axis X-X of thetorque transmitting coil 2 and the lumen 6 of the drive shaft 1 in onedirection, the distal fluid inflated support element 3 acting, duringrotation of the drive shaft 1, as a counterweight to the abrasiveelement 5 which has its centre of mass offset from the longitudinal axisX-X of the torque transmitting coil 2 and the lumen 6 of the drive shaft1 in the opposite direction.

Preferably, in this third modification of the second embodiment, thedevice also has a proximal fluid inflatable support element 23. The wall27 of the proximal fluid inflatable support element 23 defines a fluidinflatable space 70′ that extends only partially around a circumferenceof the anchoring sleeve 15′ so that, when the proximal inflatablesupport element 23 is fluid inflated, its centre of mass CM_(PC) isoffset from a longitudinal axis X-X of the torque transmitting coil 2and the lumen 6 of the drive shaft 1 in one direction, the proximalfluid inflated support element 23 acting, during rotation of the driveshaft 1, as a counterweight to the abrasive element 5 which has itscentre of mass offset from the longitudinal axis X-X of the torquetransmitting coil 2 and the lumen 6 of the drive shaft 1 in the oppositedirection.

FIG. 24 illustrates best the fourth modification of the secondembodiment of the device in which a fluid inflatable space 80 within thedistal fluid inflatable support element 3′ extends uniformly around anentire circumference of the anchoring sleeve 15′ to provide the distalsupport element 3′ with a centre of mass which lies along thelongitudinal axis X-X of the torque transmitting coil 2 and the lumen 6of the drive shaft 1 when said distal support element 3′ is fluidinflated.

Preferably, in this fourth modification of the second embodiment, thedevice also has a proximal fluid inflatable support element 23′ in whicha fluid inflatable space 100 extends uniformly around a longitudinalaxis X-X of the torque transmitting coil 2 and the lumen 6 of the driveshaft 1, therefore providing the fluid inflated proximal support element23″ with a centre of mass which lies along the longitudinal axis X-X ofthe torque transmitting coil 2 and the lumen 6 of the drive shaft 1 whenthe proximal support element 23′ is fluid inflated.

FIGS. 25 and 26 illustrate a fifth modification of the second embodimentof the device. The embodiment of FIGS. 25, 26 is similar to the fourthmodification of the second embodiment shown in FIGS. 23, 24 but differsin that the drive shaft 1 comprises inner 102 and outer 104 torquetransmitting coils. The anchoring sleeve 15′ is sandwiched between theinner 102 and outer 104 torque transmitting coils. The anchoring sleeve15′ and the inner torque transmitting coil 102 extend distally from thedistal end 114 of the outer torque transmitting coil 104 such that theinflatable support elements 3′, 23′ formed around the anchoring sleeve15′ from the fluid impermeable membrane 9 are spaced away from thedistal end 114 of the outer torque transmitting coil 104. The abrasiveclement 5 is mounted to the drive shaft 1 between and spaced away fromthe support elements 3′, 23′, therefore locating the abrasive clement 5distal to and spaced away from the distal end 114 of the outer torquetransmitting coil 104.

FIGS. 27 to 29 illustrate a sixth modification of the second embodimentof the device and its advancement across the stenotic lesion 200 to betreated. FIG. 27 shows that the rotational device of the invention hasbeen advanced across the stenotic lesion 200 to a position in which thedistal fluid inflatable support element 3 is positioned distal to thestenotic lesion 200 and the proximal fluid inflatable support element 23is intentionally positioned proximal to the stenotic lesion 200 to betreated. The device of FIG. 27 is similar to the device of FIG. 21, butdiffers in that it comprises an elongate core element 300 advanceablethrough the long lumen 6 of the drive shaft 1 to stiffen the drive shaft1 and thereby assist in the advancement of the device along the vessel222 towards and across the stenotic lesion 200.

The core element 300 is shown as partially withdrawn from the lumen 6 ofthe drive shaft 1 in FIG. 28 and completely withdrawn in FIG. 29. Itshould be noted that it is necessary to completely remove the coreelement 300 from the long lumen 6 of the drive shaft 1 and the rest ofthe device to allow attachment of a detachable fluid supply tube (notshown) to the device.

FIG. 30 illustrates an antegrade flow of pressurized fluid through thedevice and retrograde flow of fluid around the device and across thestenotic lesion 200 to be treated. It should be noted that thepressurized fluid flowing through the device is entering the treatedvessel only through the openings in the walls of the inflated supportelements 3, 23.

The device of the present invention is not rotated around a guidewire.Therefore, in order to prevent damage of the wall of the treated vesselby a distal end of the device, the distal fluid inflatable supportelement should be inflated prior to commencing high speed rotation ofthe drive shaft.

FIGS. 31 to 36 illustrate abrading of the stenotic lesion 200 by therotating abrasive element 5 and formation of layers of fluid between thewalls of the rotating fluid inflated support elements 3, 23 and theinner surface of the treated vessel 222, said layers of fluid acting asfluid bearings between the walls of the rotating fluid inflated supportelements 3, 23 and the wall 230 of the treated vessel 222. FIGS. 31 to36 show that the wall 7 of the distal fluid inflatable support element 3has an outflow opening 66 (not indicated in FIGS. 31 to 36 but indicatedin previous Figures) located such that said outflow opening 66, duringrotation of the drive shaft 1, faces an inner surface of a treatedvessel 222 so that fluid flowing through the outflow opening 66 forms alayer of fluid between the wall 7 of the rotating fluid inflated distalsupport element 3 and a wall 230 of the treated vessel 222, said layerof fluid forming a fluid beating between the wall 7 of the rotatingfluid inflated distal support element 3 and the wall 230 of the treatedvessel 222. FIGS. 31 to 36 also show that the wall 27 of the proximalfluid inflatable support element 23 has an outflow opening 99 (notindicated in FIGS. 31 to 36 but indicated in previous Figures) locatedsuch that said outflow opening 99, during rotation of the drive shaft 1,faces an inner surface of a treated vessel 222 so that fluid flowingthrough the outflow opening 99 forms a layer of fluid between the wall27 of the rotating fluid inflated proximal support element 23 and thewall 230 of the treated vessel 222, said layer of fluid forming a fluidbearing between the wall 27 of the rotating fluid inflated proximalsupport element 23 and the wall 230 of the treated vessel 222.

FIG. 37 shows the distal end portion of the device after rotation of thedevice has been stopped but prior to stopping the flow of pressurizedfluid along the lumen 6 of the drive shaft 1. Preferably, the antegradeflow FF of pressurized fluid through the device and the retrograde flowRF of fluid across the treated stenotic lesion 200 should be continuedfor at least a short period of time after rotation of the drive shaft 1has been stopped so that, any embolic particles EP remaining in thetreated vessel or which may still be released from the treated stenoticlesion 200 are entrained by the fluid which enters the treated vesselthrough the openings in the wall of the inflated distal support element3 and flows retrograde across the treated stenotic lesion 200.Preferably, all the embolic particles EP should be removed from thetreated vessel 222 and from the patient.

FIG. 38 shows the distal end portion of the device after the flow ofpressurized fluid along the lumen 6 of the drive shaft 1 has beenstopped. FIGS. 39 and 40 illustrate the removal of the device from thetreated vessel 222 and appearance of the treated vessel 222 afterremoval of the device.

FIGS. 27 to 40 illustrate removal of the stenotic lesion 200 by therotational atherectomy device with the fluid inflatable support elements3, 23 that act, during rotation of the drive shaft, as counterweights tothe eccentric or eccentrically mounted abrasive element 5. It should benoted that both modifications of the rotational atherectomy device withconcentric (symmetric) fluid inflatable support elements 3′, 23′ shownin FIGS. 23 to 26 may be equally effective or even preferred forremoving stenotic lesions in the carotid arteries. FIGS. 23 to 26 showthat the abrasive element 5 is eccentrically mounted between theconcentric fluid inflatable support elements 3′, 23′. The concentricfluid inflatable support elements 3′, 23′ of such device usually havethe fluid inflatable spaces 80, 100 that extend uniformly around thelongitudinal axis X-X of the torque transmitting coil 2 and the lumen 6of the drive shaft 1. Therefore, the walls 7, 27 of the fluid inflatableconcentric (symmetric) support elements 3′, 23′ should have at least afew openings 66, 99 equally spaced from each other around circumferencesof the walls 7, 27 of the support elements 3′, 23′ such that at any timeduring rotation of the drive shaft 1 at least one opening within eachgroup of said openings 66, 99 is facing an inner surface of a treatedvessel, so that a flow of fluid through the openings 66, 99 forms alayer of fluid between the walls 7, 27 of the rotating fluid inflatedsupport elements 3′, 23′ and a wall of the treated vessel, said layer offluid forming a fluid bearing between the walls 7, 27 of the rotatingfluid inflated support elements 3′, 23′ and the wall of the treatedvessel.

It should be also noted that the rotational atherectomy device withconcentric (symmetric) fluid inflatable support elements and concentric(symmetric) abrasive element may be useful or even preferred forremoving stenotic lesions in the curved arteries. The symmetric distaland proximal fluid inflatable support elements of such device shouldboth have at least a few openings equally spaced from each other aroundcircumference of the wall of the support element such that at any timeduring rotation of the drive shaft at least one of each of the two setsof openings is facing an inner surface of a treated vessel, so that aflow of fluid through the openings forms a layer of fluid between thewall of the rotating fluid inflated support element and a wall of thetreated vessel, said layer of fluid forming a fluid bearing between thewall of the rotating fluid inflated support element and the wall of thetreated vessel.

FIG. 41 shows yet another modification of the third embodiment of thedevice. The embodiment of FIG. 41 is similar to the embodiment of FIG.27 except that the core element 300′ shown in FIG. 41 comprises a longlumen 330 configured for transferring pressurized fluid into the lumen 6of the drive shaft through an opening 333 located in a wall of the(hollow) core element 300′. The opening(s) 333 are located adjacent to adistal end 337 of the (hollow) core element 300′. FIG. 42 shows thedevice of FIG. 41 in which pressurized fluid is flowing from the lumen330 of the core element 300′ into the lumen 6 of the drive shaft 1 suchthat a layer of fluid is formed between the wall of the core element300′ and the wall of the drive shaft 1 of the rotational atherectomydevice. FIG. 43 shows the device of FIG. 42 in which the core element300′ is being withdrawn from the lumen 6 of the drive shaft 1 and thedevice. It should be noted that continuous flow of the pressurized fluidfrom the lumen of the core element 300′ into the lumen 6 of the driveshaft 1 is reducing friction between the core element 300′ and the wallof the lumen 6 of the drive shaft 1 and thereby is assisting in removingthe core element from the device without changing position of the devicein the treated vessel.

FIG. 44 shows the device of FIG. 42 after flow of pressurized fluid hasbeen initiated through the lumen 320 of the core element 300′ and therest of the device at a fluid flow rate which is sufficient to inflatethe distal support element 3 and anchor it distal to the stenotic lesion200. FIG. 45 illustrates how the anchoring of the inflated distalsupport element 3 against the stenotic lesion 200 is assisting inremoving the core element 300′ from the lumen 6 of the drive shaft 1without changing the position of the rest of the device in the treatedvessel. It should be noted that the stiffening of the drive shaft 1 bythe pressure of the fluid on the wall of the lumen 6 of the drive shaft1 is also assisting in the removal of the core element 300′ from thedrive shaft 1 without changing the position of the rest of the device inthe treated vessel.

FIGS. 46 and 47 illustrate the fourth embodiment of the device in whichthe wall 7″ of the distal fluid inflatable support element 3″ is madefrom a fluid impermeable stretchable membrane 9″. The stretchablemembrane 9″ proximal to the distal fluid inflatable support element 3″is sandwiched between the torque transmitting coil 2 of the drive shaft1 and a non-stretchable sleeve 500. Preferably, the fluid impermeablestretchable membrane 9″ extends around the torque transmitting coil 2 inproximal direction to form the wall 27″ of the proximal fluid inflatablesupport element 23″. The non-stretchable sleeve 500 may extend aroundthe stretchable membrane uninterrupted between the distal and proximalfluid inflatable support elements as shown in FIG. 46 it may be dividedin two sections 510, 520 as shown in FIGS. 47 and 48. FIGS. 47 and 48show that the sections 510, 520 of the non-stretchable sleeve 500 aredisposed on either side of the abrasive element 5. FIGS. 46 to 48 alsoshow a second long, non-stretchable sleeve 600 which overlaps thestretchable membrane 9″ for a short distance proximal to the proximalfluid inflatable support element 23″ and extends in a proximal directionaround the torque transmitting coil 2 towards the proximal end of thedrive shaft 1.

It should be noted that the fluid inflatable support elements may beformed either from stretchable fluid impermeable sleeves or fromnon-stretchable sleeves which have a larger diameter in the areas of thefluid inflatable support elements and which are simply furled around thedrive shaft when drive shaft is advanced to, and across, the lesion tobe treated.

FIG. 49 illustrates the fifth embodiment of the device. The embodimentof FIG. 50 is similar to the embodiment of FIG. 27 except that the lumen6′ of the drive shaft 1 includes proximal and distal portions havingdifferent cross-sectional areas. The proximal portion 700 of the thelumen 6′ has a larger cross-sectional area relative to thecross-sectional area of the distal portion 800 of the lumen 6′ so that,per unit of length, hydraulic resistance to fluid flow of the proximalportion 700 of the lumen 6′ is less than the hydraulic resistance tofluid flow of the distal portion 800 of the lumen 6′.

It should be noted that the fluid inflatable support elements 3, 23 ofthe fifth embodiment shown in FIG. 49 are illustrated as being formedfrom a non-stretchable membrane. The non-stretchable walls 7, 27 of thefluid inflatable support elements 3, 23 should be simply furled aroundthe drive shaft when the device is advanced to, and across, the stenoticlesion to be treated.

It should be also noted that the fluid inflatable support elements shownin FIG. 49 and in any of FIGS. 1 to 45 may be formed from a stretchablemembrane.

1. A rotational atherectomy device for abrading a stenotic lesion from avessel of a patient, comprising a flexible drive shaft which extendstowards a distal end of the device, a distal fluid inflatable supportelement located at a distal end of the drive shaft and an abrasiveelement mounted to the drive shaft proximal to and spaced away from thedistal fluid inflatable support element, both the abrasive element andthe distal fluid inflatable support element being rotatable togetherwith the drive shaft, the drive shaft comprising a torque transmittingcoil which defines a long lumen of the drive shaft, the distal fluidinflatable support element being formed from a fluid impermeablemembrane that permanently crosses a longitudinal axis common to thetorque transmitting coil and the lumen of the drive shaft at the distalend of the device, thereby preventing pressurized fluid flowing alongthe lumen of the drive shaft from entering the vessel in the directionof said longitudinal axis so that fluid has to pass through the fluidinflatable support element, inflating said support element and exitingfrom the device through an outflow opening in the fluid inflatablesupport element in a direction different from the direction of thelongitudinal axis of the coil and the lumen.
 2. The device according toclaim 1, wherein the distal fluid inflatable support element has a wall,said wall being formed from the fluid impermeable membrane thatpermanently crosses the longitudinal axis of the torque transmittingcoil and the lumen of the drive shaft.
 3. The device according to claim2, wherein the wall of the distal fluid inflatable support elementextends around the torque transmitting coil of the drive shaft. 4.(canceled)
 5. The device according to claim 1, wherein the torquetransmitting coil comprises at least one space which separatesindividual windings of the coil, said space allowing fluid communicationbetween the lumen of the drive shaft and the distal fluid inflatablesupport element.
 6. The device according to claim 1, comprising ananchoring sleeve underlying the fluid impermeable membrane along atleast a distal end portion of the drive shaft, the fluid impermeablemembrane being attached to said anchoring sleeve proximal to the distalfluid inflatable support element.
 7. The device according to claim 1,wherein the torque transmitting coil has proximal and distal ends and ananchoring sleeve is disposed around at least a distal end portion of thetorque transmitting coil
 8. The device according to claim 6, wherein thetorque transmitting coil has proximal and distal ends and the anchoringsleeve extends distally from the distal end of the coil such that thedistal inflatable support element formed around the anchoring sleevefrom the fluid impermeable membrane is spaced away from the distal endof the torque transmitting coil, the abrasive element being disposedaround at least a portion of the circumference of the anchoring sleeve.9. (canceled)
 10. (canceled)
 11. The device according to claim 6,wherein the anchoring sleeve is closed at its distal end.
 12. The deviceaccording to claim 6, wherein the anchoring sleeve has an openingtherein associated with the distal fluid inflatable support element toallow pressurised fluid to flow through said opening into the distalfluid inflatable support element from the lumen of the drive shaft. 13.The device according to claim 11, wherein the distal end of the deviceand the closed distal end of the sleeve are spaced away from each otherto form a soft atraumatic cushion between the distal end of the deviceand the closed distal end of the anchoring sleeve.
 14. The deviceaccording to claim 6 comprising an elongate core element advanceablethrough the lumen of the drive shaft to stiffen the drive shaft andthereby assist in the advancement of the drive shaft along the vesseltowards the treatment site.
 15. The device according to claim 53,wherein the elongate core element has a distal end configured foroperational engagement with the distal end of the anchoring sleeve. 16.The device according to claim 14, wherein the elongate core element isconfigured to be removed from the device after the distal end of thedevice has been advanced to the treatment site so that a detachablefluid supply tube can be attached to the device.
 17. The deviceaccording to claim 14, wherein the elongate core element includes alumen for the passage of fluid therealong.
 18. The device according toclaim 17, wherein the elongate core element has at least one openinglocated at or proximal to its distal end, said opening providing fluidcommunication between the lumen of the elongate core element and thelumen of the drive shaft.
 19. (canceled)
 20. The device according toclaim 11, wherein the anchoring sleeve comprises at least one openinglocated proximal to the closed distal end of the sleeve, said openingproviding fluid communication between the lumen of the drive shaft andthe distal fluid inflatable support element.
 21. The rotationalatherectomy device according to claim 2, wherein the distal fluidinflatable support element has, when inflated, a centre of mass whichlies along the longitudinal axis of the torque transmitting coil and thelumen of the drive shaft.
 22. The rotational atherectomy deviceaccording to claim 2, wherein a fluid inflatable space within the distalfluid inflatable support element extends uniformly around thelongitudinal axis of the torque transmitting coil and the lumen of thedrive shaft to provide the distal support element with a centre of masswhich lies along the longitudinal axis of the torque transmitting coiland the lumen of the drive shaft when said distal support element isfluid inflated.
 23. The rotational atherectomy device according to claim2, wherein there is a plurality of openings in the wall of the fluidinflatable distal support element, said openings being located aroundthe circumference of the wall of the fluid inflatable distal supportelement such that, during rotation of the drive shaft, at least some ofsaid openings face an inner surface of a treated vessel, so that flowsof fluid through the openings form a layer of fluid between the outerwall of the fluid inflated distal support element and a wall of thetreated vessel, said layer of fluid forming a fluid bearing between theouter wall of the rotating fluid inflated distal support element and thewall of the treated vessel.
 24. The rotational atherectomy deviceaccording to claim 23, wherein the device comprises a proximal fluidinflatable support element located proximal to and spaced away from theabrasive element, the proximal fluid inflatable support element havingan outer wall.
 25. (canceled)
 26. The device according to claim 24,wherein the proximal fluid inflatable support element has, wheninflated, a centre of mass which lies along the longitudinal axis of thetorque transmitting coil and the lumen of the drive shaft.
 27. Therotational atherectomy device according to claim 24, wherein a fluidinflatable space within the proximal fluid inflatable support elementextends uniformly around a longitudinal axis of the torque transmittingcoil and the lumen of the drive shaft to provide the proximal supportelement with a centre of mass which lies along the longitudinal axis ofthe torque transmitting coil and the lumen of the drive shaft when saidproximal support element is fluid inflated.
 28. The rotationalatherectomy device according to claim 24, wherein there is a pluralityof openings in the wall of the fluid inflatable proximal supportelement, said openings being located around the circumference of thewall of the fluid inflatable proximal support element such that, duringrotation of the drive shaft, at least some of said openings face aninner surface of a treated vessel, so that flows of fluid through theopenings form a layer of fluid between the outer wall of the fluidinflated proximal support element and a wall of the treated vessel, saidlayer of fluid forming a fluid bearing between the outer wall of therotating fluid inflated proximal support element and the wall of thetreated vessel.
 29. (canceled)
 30. The device according to claim 1,wherein the abrasive element has a centre of mass which is offset in aradial direction from the longitudinal axis of the coil and the lumen ofthe drive shaft.
 31. (canceled)
 32. (canceled)
 33. (canceled) 34.(canceled)
 35. (canceled)
 36. (canceled)
 37. (canceled)
 38. (canceled)39. (canceled)
 40. (canceled)
 41. (canceled)
 42. (canceled) 43.(canceled)
 44. The rotational atherectomy device according to claim 24,wherein the walls of both inflatable support elements are made from acontinuous stretchable membrane, said fluid impermeable stretchablemembrane being sandwiched between the torque transmitting coil and atleast one non-stretchable sleeve, the non-stretchable sleeve beingdisposed around the stretchable membrane between the fluid inflatablesupport elements.
 45. The rotational atherectomy device according toclaim 44, wherein the non-stretchable sleeve is formed in two sections,each section being disposed on either side of the abrasive element. 46.(canceled)
 47. (canceled)
 48. (canceled)
 49. The rotational atherectomydevice according to claim 1, wherein the lumen of the drive shaft hasproximal and distal portions, the proximal portion of the lumen having alarger cross-sectional area relative to the cross-sectional area of thedistal portion of the lumen so that per unit of length hydraulicresistance to fluid flow of the proximal portion of the lumen is lessthan the hydraulic resistance to fluid flow of the distal portion of thelumen.
 50. The rotational atherectomy device according to claim 24,wherein all the pressurised fluid which flows through the lumen of thedrive shaft exits from the device into the vessel through opening(s) inthe wall(s) of the fluid inflatable support elements.
 51. (canceled) 52.(canceled)
 53. The device according to claim 13, comprising an elongatecore element advanceable through the lumen of the drive shaft to stiffenthe drive shaft and thereby assist in the advancement of the drive shaftalong the vessel towards the treatment site.